JPH0777071A - Throttle valve drive device of engine for outboard motor - Google Patents

Abstract

PURPOSE:To stabilize rotation of an engine in away that a coupling rod is brought into a state to be difficult for thermal expansion thereof to exerise influence and to perform smooth operation of a throttle even when a manufacture error is produced. CONSTITUTION:Coupling rod mounting parts are arranged to the throttle valves 26 of two carburetors 18 located closer to a central part point-symmetrically around a throttle shaft 27. The coupling rod mounting parts on the same side of the two throttle levers 26 are intercoupled through a coupling rod 30. The coupling rod mounting part on the other side is coupled to the throttle levers 26 thereabove and therebelow through respective coupling rods 30. The third throttle lever 26 from below is not rotated and a throttle opening change amount of the topmost carburetor 18 is reduced to 1/3. Even when the throttle lever 26 is displaced from a regular position, it is not forcibly pushed by the coupling rod 30 and rotation is smoothed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throttle valve driving device for an outboard engine, which rotates the throttle levers of the throttle valves of a plurality of carburetors arranged in parallel by a connecting rod.

[0002]

2. Description of the Related Art Conventionally, as a throttle valve drive device of this type, there is one disclosed in, for example, Japanese Utility Model Laid-Open No. 2-119947. In the throttle valve drive device disclosed in this publication, the throttle levers of the three carburetors fixed side by side on the intake manifold are connected by one connecting rod, and one of the three throttle levers is connected. By operation, the other two throttle levers were configured to rotate in synchronization with this. In addition,
Of the three carburetors, the throttle lever of the carburetor located at one end in the juxtaposed direction was connected to the throttle operating means.

The connecting rod is formed of a resin portion rotatably connected to the throttle lever and a stainless steel metal rod interconnecting the resin portions of the throttle levers.

[0004]

However, when the throttle valve drive device constructed as described above is used, the idling speed may become unstable or the engine may stall. This is because the three vaporizers are out of synchronization due to the difference between the thermal expansion amount of the intake manifold and the thermal expansion amount of the connecting rod.

That is, when the engine is operating at high speed, the intake manifold is cooled by the endothermic action when a large amount of fuel is made to flow and the fuel is vaporized, whereas the connecting rod is exposed to the air heated by the high temperature engine. Because the temperature will rise. More specifically, the distance between the carburetors that changes according to the thermal expansion of the intake manifold and the distance between the swinging ends of the throttle levers that change according to the thermal expansion of the connecting rod do not match. The throttle openings of the individual carburetors will not match. Therefore, when the throttle opening / closing means is connected to the throttle lever of the carburetor located at one end of the three carburetors in the juxtaposed direction, the carburetor farthest from the carburetor is most likely to be out of synchronization. If the three carburetors are out of synchronization in this way, the idling speed will become unstable or the engine will stall when the throttle is fully opened and the engine is idling.

Further, in this conventional throttle valve drive device, the connecting rod may not operate smoothly. this is,
This is because the connecting portion of the throttle lever with the connecting rod is not necessarily arranged on the same straight line among the three carburetors due to manufacturing errors in the intake manifold and the carburetor.
To be more specific, when a linear connecting rod is attached to these throttle levers, the throttle levers located at positions deviated from the straight lines are forcibly pushed, and a large load is applied to the bearings of the throttle shaft in the radial direction. Will end up. Therefore, it becomes difficult for the throttle shaft to rotate, and as described above, the connecting rod malfunctions.

The present invention has been made in order to solve such problems, and it is possible to stabilize the rotation of the engine while avoiding the influence of thermal expansion of the connecting rod as much as possible, and to manufacture the engine. The purpose is to enable smooth throttle operation even if there is an error.

[0008]

A throttle valve drive system for an outboard engine according to the present invention comprises a plurality of carburetors arranged side by side on a throttle shaft of the carburetor excluding both ends in the arranging direction.
A throttle lever having a connecting rod mounting portion provided at a position symmetrical about the throttle shaft is fixed, and the connecting rod mounting portion at one end of the throttle lever is adjacent to one side in the carburetor parallel installation direction via the connecting rod. In addition to being connected to the throttle lever of the carburetor, the connecting rod attachment portion at the other end is connected to the throttle lever of the carburetor adjacent to the other side in the carburetor juxtaposition direction via the connecting rod.

[0009]

When the connecting rod connecting the throttle lever to which the throttle opening / closing means is connected and the throttle lever adjacent to this throttle lever expands due to thermal expansion, the connection connected to the other end of the adjacent throttle lever. The rod moves to the side of the throttle lever to which the throttle opening / closing means is connected by the amount of extension. Since the moving connecting rod is also expanded by thermal expansion by the same amount, the position of the other end of the connecting rod does not change. Therefore, the connecting rod connected to the other end of the moving connecting rod via the throttle lever only extends to the opposite side by the amount of extension of itself. That is, when the throttle opening / closing means is connected to the carburetor at one end of the carburetor in the juxtaposed direction, the connecting portion of the connecting rod that is connected to the throttle lever of the carburetor at the other end of the juxtaposed direction has only one throttle lever. It is closer to the throttle lever on the side of the throttle opening / closing means than when connected.

Further, the connecting rod only connects the throttle levers of the carburetors adjacent to each other, and even if the position of one throttle lever deviates from the normal position, the connecting angle of the connecting rod becomes the normal angle. Both throttle levers are connected simply by changing them.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to FIGS. FIG. 1 is a right side view of an outboard motor equipped with a throttle valve drive device according to the present invention, and FIG. 2 is an enlarged side view showing a throttle valve drive device for an outboard engine according to the present invention.

In these drawings, reference numeral 1 denotes an outboard motor, and this outboard motor 1 is provided with a swivel bracket 2 and a clamp bracket 3 at its front part, and can be vertically swung on a stern plate (not shown) as is well known in the art. Moreover, it is structured so that it can be steered. Reference numeral 4 denotes an engine, which is a four-cycle four-cylinder type engine and is fixed to an upper portion of the guide exhaust 5. 6 is an upper case fixed to the lower part of the guide exhaust 5, 7 is a lower case connected to the lower end of the upper case 6, and 8 is a propeller attached to the lower case 7. This propeller 8
Is driven by the drive shaft 10 connected to the crankshaft 9 of the engine 4 and a shift mechanism (not shown) provided at the lower end of the drive shaft 10 so that the power of the engine 4 is transmitted to rotate. It is configured.

Reference numeral 11 is a lower cowling that covers the upper portions of the guide exhaust 5 and the upper case 6, and 12 is an upper cowling that covers the engine 4 by closing the upper opening of the lower cowling 11, and the upper cowling 12 is attached to the lower cowling 11. It is detachably attached.

The engine 4 is formed by orienting the crankshaft 9 in the vertical direction and arranging four cylinders in the vertical direction and in the front-rear direction. The crankshaft 9 is positioned on the front side and attached to the guide exhaust 5. Has been. Reference numeral 13 is a crankcase of the engine 4, 14 is a cylinder block, 15 is a cylinder head, and 16 is a cylinder head cover.

A belt type transmission device 17 for transmitting the rotation of the crankshaft 9 to a valve operating cam shaft (not shown) of the cylinder head 15 is mounted on the upper portion of the engine 4. It should be noted that the valve operating camshaft is a single intake valve (not shown) and exhaust valve (not shown) in the cylinder head 15.
It is structured to drive.

Reference numeral 18 is a vaporizer of the engine 4. The carburetor 18 is provided on the right side of the engine 4 for each cylinder, and as shown in FIG. 2, four carburetors 18 are arranged vertically on the intake manifold 15a projecting on the right side of the cylinder head 15 for each cylinder and integrally formed. It is installed in a connected state.
Reference numerals 19 and 20 denote connecting plates for connecting the carburetors 18 for the respective cylinders to each other.
0 is formed of a single stainless steel plate material extending in the direction in which the carburetors 18 are arranged in parallel, the connecting plate 19 is arranged on the downstream side of the intake flow in the carburetor 18, and the connecting plate 20 is arranged on the upstream side. It is arranged. Each carburetor 18 has its left side surface (a side surface on the back side of the paper surface in FIG. 2) screwed to the longitudinally extending portions (not shown) of these connecting plates 19 and 20. That is, in this embodiment, the four carburetors 18 are arranged such that one connecting member (the connecting plate 19 or the connecting plate 20) extending in the parallel direction is arranged at the front and the rear.
They will be connected to each other by 9, 20.

Then, these connecting plates 19, 20 are connected.
The carburetor assembly formed by connecting the carburetors 18 is fixed between the downstream connecting plate 19 and the intake manifold 15a via a heat insulating plate 21 made of a rubber plate and a connecting plate 22. There is. The heat insulating plate 21 is fitted to the connecting plate 19 and the connecting plate 22 via a fitting connecting structure (not shown), and the connecting plate 19 and the connecting plate 22 are attached.
And are connected via this heat insulating plate 21. Further, the connecting plate 22 is fixed to the intake manifold 15a by a mounting bolt indicated by reference numeral 23 in FIG.

An intake silencer 24 is fixed by a mounting bolt 25 to the connecting plate 20 located upstream of the intake flow in the carburetor 18. The intake silencer 24 is configured to suck the air in the cowling from the lower portion on the front side and guide the air to the carburetor 18 via an intake pipe 24a provided individually for each carburetor 18. This vaporizer 1
The intake pipes 24 a for each 8 are fixed to the connecting plate 20.

A throttle lever 2 for opening and closing an internal throttle valve (not shown) is provided on the right side of the carburetor 18.
6 are arranged. The throttle lever 26 is fixed to the shaft end of the throttle shaft 27, and is biased by a return spring 28 in the direction of closing the throttle valve (counterclockwise in FIG. 2). The throttle shaft 27
Has a fixed throttle valve, and is rotatably supported by a case of the carburetor 18 via a bearing (not shown).

Further, the throttle lever 26 provided on the lowermost carburetor 18 of the four carburetors 18
The rod type throttle opening / closing means 29 is rotatably connected to an arm extending downward from the throttle shaft connecting portion. The rod-type throttle opening / closing means is extended from the throttle lever 26 to the front, and is configured to move forward / backward in the front-rear direction by a driver manually operating an accelerator operator (not shown). Note that, in FIGS. 1 and 2, an idling adjustment mechanism, an acceleration pump mechanism and the like which are usually provided in the carburetor 18 are omitted.

Further, among the four carburetors 18, the throttle levers 2 of the second and third carburetors 18 from the bottom are respectively provided.
An arm 6 extends to the front side and the rear side of the throttle shaft 27, and a connecting rod attachment portion is provided at a tip end portion of the arm and at a position symmetrical about the throttle shaft 27. .

The throttle levers 26 of the respective carburetors 18 are connected to each other via the connecting rod 30 according to the present invention and are constructed so as to rotate synchronously. The connecting rod 30 is formed of a rod body 31 made of a stainless steel rod and connecting members 32 provided at both ends of the rod body 31 and rotatably connected to the throttle lever 26, and are adjacent to each other. Only the throttle levers 26 of the carburetor 18 are connected.

That is, as shown in FIG. 2, the lowermost throttle lever 26 and the second lowest throttle lever 26 are connected by a connecting rod 30 located rearward of the throttle shaft 27, and The second throttle lever 26 and the third throttle lever 26 from the bottom are connected by a connecting rod 30 located in front of the throttle shaft 27, and further the third throttle lever 26 from the bottom and the uppermost position. The throttle lever 26 is connected by a connecting rod 30 located on the rear side of the throttle shaft 27. The three connecting rods 30 are formed so that their entire lengths are equal.

In the throttle valve drive system in which the throttle levers 26 of the adjacent carburetors 18 are connected by the three connecting rods 30 as described above, the carburetors are caused by manufacturing errors of the intake manifold 15a and the carburetor 18. When the throttle levers 26 are displaced from their proper positions in the state where 18 is attached to the intake manifold 15a, the adjacent throttle levers 26 are connected by simply changing the attachment angle of the connecting rod 30 to the proper angle. To be done.

After connecting the connecting rod 30 to each throttle lever 26 as described above, the rod-type throttle opening / closing means 29 is opened from the throttle fully closed state shown in FIG.
When is manually moved to the front, the throttle lever 26 located at the lowermost side rotates clockwise with the throttle shaft 27 around this shaft in FIG. 2, and the connecting rod 30 connected to the throttle lever 26 moves downward. Move to.

As a result, the second from the bottom throttle lever 26 connected to the connecting rod 30 rotates clockwise, and similarly, the third and uppermost throttle levers 26 from the bottom rotate clockwise, respectively. become. Therefore, the throttle valves of the carburetors 18 are simultaneously opened with the same opening.

When the temperature inside the cowling rises as the engine 4 is operated, the connecting rod 30 expands due to thermal expansion. The operation of this throttle valve driving device when the connecting rod 30 extends will be described below. Since the lowermost throttle lever 26 is connected to the rod-type throttle opening / closing means 29 so that the rotational position does not change, the lower connecting rod 30 connected to this throttle lever 26 extends upward due to thermal expansion. The second throttle lever 26 from the bottom connected to the upper end of the connecting rod 30 slightly turns counterclockwise in FIG. 2, and the central connecting rod 30 connected to the front end of the throttle lever 26. Moves slightly downward.

At this time, the central connecting rod 30 also extends vertically due to thermal expansion, and the moving amount when moving downward is equal to the extending amount, so the central connecting rod 30
The upper end position of does not change. That is, the throttle lever 26 connected to the upper end of the central connecting rod 30 does not rotate in either the left or right direction. In other words, in the third carburetor 18 from the bottom, the throttle opening does not change despite the thermal expansion of the connecting rod 30. Therefore, the upper connecting rod 30 extends upward by its own thermal expansion amount.

Therefore, the lower connecting rod 30 connecting the lowermost throttle lever 26 to which the throttle opening / closing means 29 is connected and the second lowest throttle lever 26 adjacent to the throttle lever 26 is thermally expanded. The second throttle lever 26 from the bottom
The central connecting rod 30 connected to the other end of the above moves downward by the amount of extension. Since the central connecting rod 30 is also expanded by thermal expansion by the same amount as the expansion amount, the position of the upper end thereof does not change. Therefore, the upper connecting rod 30 connected to the other end of the central connecting rod 30 via the third throttle lever 26 from the bottom only extends upward by the amount of its own extension. That is, when the throttle opening / closing means 29 is connected to the carburetor 18 at the lower end in the juxtaposed direction of the carburetor 18, the connecting portion of the connecting rod 30 connected to the throttle lever 26 of the carburetor 18 at the upper end in the juxtaposed direction is one. It is closer to the throttle lever 26 located at the lowermost side as compared with the case where all the throttle levers 26 are connected. As a result, the throttle opening of the uppermost carburetor 18 of the four carburetors 18 can be prevented from changing as much as possible.

When the structure in which the four carburetors 18 are connected by the three connecting rods 30 as in this embodiment is adopted, when the throttle levers 26 of all the carburetors 18 are connected by one connecting rod. In comparison, the amount of change in the throttle opening of the carburetor 18 located on the uppermost side is about 1/3.

Further, the connecting rod 30 only connects the throttle levers 26 of the carburetors 18 adjacent to each other, and even if the position of one throttle lever 26 is deviated from the normal position, the mounting angle of the connecting rod 30 is increased. Both throttle levers 2 just by changing the
6 are connected. Therefore, the throttle lever 26 will not be forced by the connecting rod 30.

In this embodiment, four vaporizers 18 are arranged in parallel, but the present invention is not limited to such a limitation, and the number of vaporizers 18 may be three or four, for example. It may be more than one.

[0033]

As described above, the throttle valve drive system for an engine for an outboard motor according to the present invention includes a plurality of carburetors, which are arranged in parallel, except for both ends in the parallel direction. Secure a throttle lever with a connecting rod mounting part provided in a point symmetry about the axis, and connect the connecting rod mounting part at one end of this throttle lever to one side in the carburetor parallel installation direction via the connecting rod. Since it is connected to the throttle lever of the carburetor, and the connecting rod mounting portion at the other end is connected to the throttle lever of the carburetor adjacent to the other side in the carburetor juxtaposition direction via the connecting rod, the throttle opening / closing means is connected to the throttle lever. When the connecting rod that connects the throttle lever adjacent to this throttle lever expands due to thermal expansion, the adjacent throttle Connecting rod connected to the other end of Rureba moves to a throttle lever side in which the throttle opening and closing means by said elongation amount are connected. Since the moving connecting rod is also expanded by thermal expansion by the same amount, the position of the other end of the connecting rod does not change. Therefore, the connecting rod connected to the other end of the moving connecting rod via the throttle lever only extends to the opposite side by the amount of extension of itself.

That is, when the throttle opening / closing means is connected to the carburetor at one end of the carburetor in the arranging direction, the connecting portion of the connecting rod connected to the throttle lever of the carburetor at the other end of the arranging direction is one. It is closer to the throttle lever on the throttle opening / closing means side compared to the case where the throttle lever is connected.

Therefore, it is possible to suppress the change in the throttle opening of the carburetor farthest from the throttle opening / closing means as much as possible, and to avoid the influence of the thermal expansion of the connecting rod as much as possible. The rotation of can be stabilized.

Further, the connecting rod only connects the throttle levers of the carburetors adjacent to each other, and even if the position of one throttle lever deviates from the normal position, the connecting angle of the connecting rod becomes the normal angle. Since both throttle levers are connected simply by changing them, the throttle operation can be performed smoothly even if there is a manufacturing error.

[Brief description of drawings]

FIG. 1 is a right side view of an outboard motor equipped with a throttle valve drive device according to the present invention.

FIG. 2 is an enlarged side view showing a throttle valve drive device for an outboard engine according to the present invention.

[Explanation of symbols]

 4 engine 18 carburetor 26 throttle lever 27 throttle shaft 29 rod type throttle opening / closing means 30 connecting rod

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location // B63H 20/00 (72) Inventor Yasuhiko Shibata 1400 Shimbashi-cho, Hamamatsu-shi, Shizuoka Sanshin Industrial Co., Ltd. In the company

Claims (1)

[Claims] 1. In a throttle valve drive device for an outboard engine, wherein at least three or more carburetors are arranged in parallel, the throttle levers of the throttle valves of the carburetors are rotated synchronously by a connecting rod. To the throttle shaft of the carburetor excluding both ends in the parallel installation direction, a throttle lever having a connecting rod attachment portion provided at a position symmetrical about the throttle shaft is fixed, and the connecting rod at one end of the throttle lever is fixed. The mounting part is connected to the throttle lever of the carburetor adjacent to the carburetor side by side via the connecting rod, and the connecting rod attachment part on the other end is adjacent to the carburetor side by side via the connecting rod. A throttle valve drive device for an outboard engine, which is connected to a throttle lever of a vessel.